A couple of months back, the BBC began taking advantage of a feature of the Freeview HD spec that allows the broadcaster to dynamically select between 1080p / 25fps and 1080i / 25fps transmission. These settop boxes are mandated to be able to output 1080p / 50fps and a recent software update means that Freeview HD STBs can now automatically detect 1080p material and change encoding appropriately.
"The Freeview HD platform has always been specified to provide a 1080p25 capability. This is why STBs are mandated to have a 1080p50 output to enable seamless up-conversion to a mode which is guaranteed to be present in all display devices," Phil Layton explained via the BBC’s R&D blog, adding that though a great deal of material is shot natively at 1080p25, "within a single programme, [1080i] may be used for moving credits, cross-fades and studio shots whereas progressive may be used for location shot material."
While the ability to switch back and forth between 1080p and 1080i is definitely good news, it seems not all viewers are having a good experience with the new, high definition transmissions. The whole reason the Beeb's new approach came to light was because owners of Sony HD TVs are complaining about audio drop-outs. This is said to be occurring as the TVs' integrated tuner-fed decoders struggle with the change in format. Beleaguered Sony says it's working on a fix and will provide more information in the next week or so.
"Sony is testing a fix to this problem, and we will have more information within the next seven to 10 days, as there are other countries with HD broadcasts, we are checking to ensure that they are not affected by any changes made," the company told What Hi-Fi in a statement.
"This fix will improve the transition from 1080i to 1080p and back, to ensure the audio, picture and data information are not interrupted."